In sub-Saharan Africa is it possible to protect hard-pressed human populations and the world's most endangered wildlife? That's a challenge for Thuli Brilliance Makama who has been awarded the prestigious Goldman environmental prize for her environmental campaigning in the tiny kingdom of Swaziland. The rights of some of Africa's poorest people, or the survival of species like the black rhino - which matters more? Thuli Brilliance Makama talks to Stephen Sackur.